Apparatus for obtaining nitrogen from air.



G. BLAGBURN. APPARATUS FOR OBTAINING NITROGEN FROM AIR. APPLICATIONFILED rmms, 1910.

993,017. Fm. 1 Patented May 23,1911.v

WITNESSES INVENTOR I W1 .59; Iii-m4 ATTORNEY bustion, thus solving theUNITED STATES PATENT oE IoE:

CHARLES BLAGIBURN, OF- SAN FRANCISCO, CALIFORNIA, ASSIGNOB TO HIMSELF,

. TRUSTEE.

Specification of Letters latcnt.

Original application iiled November 27, 1907, Serial No. 404,120.Divided and this application died Feb- Patented May 23, 1911.

ruary 16, 1910. Serial No. 544,212.

To all whom it may concern:

Be it known that I, CHARLES BLAGBURN, a citizen of the United States,residing at San Francisco, in the count of San Francisco and State ofCalifornia, have invented new and useful Improvements in Apparatus forObtaining Nitrogen from Air, of which the following is a specification.

The object of the present invention is to provide an apparatus forobtaining from the air practically pure nitrogen, the presentappllcation being a division of an ap lication filed by me November 27,1907, erial No. 404,120. I

The problem of obtaining nitrogen from the air at a low cost has becomein recent times extremely important; first, on account of'the greatlyincreased demand for nitrate fertilizers to enrich poor or exhaustedsoils; second, on account of the extensive and increasing use of cyanidsin minin and the arts; and, third, on account of t e utility of nitrogengas as a preservative medium for preserving edibles and other perishablearticles in air-tight receptacles.

I have invented an apparatus, by means of which sulfur may be so burnedon a commercial scale as to remove all of the oxygen from the stream ofair supplied for its comnitrogen problem, since this a paratus, onaccount of the cheapness of sul ur, enables the nitrogen to be obtainedat quite a low cost.

In the accompanyin drawing, Figure 1 is a diagrammatic sectional view ofmy apparatus; Fig. 2 is a longitudinal section of the furnace; Fig. 3 isa transverse section thereof.

1 indicates a combustion chamber, which is very shallow in proportion toits length and width, in order to ex ose a large surface of sulfur tothe air 0 combustion. To said combustion chamber sulfur is fed by meansof a charging assage 2 which can be closed when desired means'of asuitable cover 3. Beneath sai combustion chamber is a fire box 50,having a grate 51 and a flue 52 in which a fire can be kindled to heatthe sulfur initially, or if desired, suitable fuel can be burned duringthe process, although I have not found this to be necessary. The bottom4 of the combustion chamber 1 slopes very sli htly, (the slope beingexaggerated in the rawing) from front to "rear, to insure the meltedsulfur flowing over the entire surface of said bottom. In saidcombustion chamber and extending across its entire width is an airheating chamber 5, which has a bottom 6, which thus forms the top of thecombustion chamber. It slopes downward from a point near the chargingend of the combustion chamber to the outlet 7 thereof. Into said heatingchamber air is drawn by suction, as hereinafter described, throu h apipe 8, and im inges upon the sloping bottom thereof. T eair in thisheating chamber, being hi hly heated by the combustion of sulfur in thechamber beneath, emerges from the heating chamber through downwardlextending ipes 9, by which means it is ed to the su fur in the bottom ofthe combustion chamber. How.- ever while it is thus desirable in manycases, as or makin nitrogen on a very large scale, to heat t e air eforesupplying it to the sulfur, I am enabled to carry out my process byburning the sulfur with air not eated before being introduced into thecombustion chamber, this air being supplied through the charging opening2, the cover 3 being thus removed.

In order to successfully practice this invention, two main conditionsare necessary. First, the furnace must be so constructed that the air ofcombustion is compelled, before escaping from the combustion chamber, topass into close proximity to the sulfur, which, near the point of exit,would be in a molten condition with sulfur va ors arising therefrom;and, secondly, t e sulfur must be in excess, or at any rate no more airmust be supplied to the sulfur than is necessary to supply the oxygenfor combustion thereof.

As will hereinafter appear, the gases from the furnace have to passthrough a long series of purifying chambers, and, therefore, in order tosupply any air to the furnace, a suction ump is necessary at the end ofsaid series. ow, for a given rate of feeding the sulfur, the suctionpump must be so operated that the current of air supplied thereby isnever more than necessary, as above mentioned. So long as sulfur vaporasses off unconsumed, as evidenced by the ormation of sublimed sulfur inthe condensing chambers, the process is being properly carried out.

I realize .that the a paratus may be greatly varied in form anconstruction, and still satisfy the other essential condition, namely,that the air be compelled to pass into close proximity to the highlyheated sulfur, so that no oxygen can escape, and all such variations Iregard as within the scope of my invention.-

From the outlet 7 of the furnace, the gases pass upward by a pipe 10.Should any oxygen have been unconsumed by the sulfur before reaching thepipe 10, it will certainly combine with the excess sulfur 'vapor therein, the pipe 10 being intensely hot. From the pipe 10 the gases,consisting of nitrogen, sulfurous anhydrid, sulfur vapor, and a smallamount of steam, due to the presence of moisture in the atmospheric airsupplied to the furnace, then pass in Succession through two sublimingchambers 11, 12, which are suflicient to condense and precipitate in theform of sublimed sulfur nearly all the excess of sulfur which has passedoff in the form of vapor.

From the top of the second subliming chamber 12, the nitrogen andsulfurous anhydrid pass into the top of a sulfurous acid tower 13, inthe top of which is arranged a spraying device 14 which sprays waterthereinto. In said tower are placed one above the other alternatingtrays 18, 19, of two series, the trays 18 of one series having a centralpassage 20, and those of the other having an annular space 21 betweenthe side of the tray and the side of the tower, through which the gasescan. pass. The water is compelled to flow from one tray to the nextbelow it either through a central opening 20, or through one of theannular passages '21. This water, if not too much, passing through thenitrogen and sulfurous anhydrid gases, forms from the latter strongsulfurous acid solution, which is collected by a pipe15 from a liquidseat 16 at the bottom of said tower. The nitrogen and part of thesulfurous anhydrid gases then pass into the bottom of a second tower 17,,into the top of which water is also sprayed, the amount of watersupplied in this tower being reater than that in the first tower, sothat su furous acid solution in much larger quantity, but greatlydiluted, is collected therefrom.

From the tower 17 the gases pass through perforations 22 of a. supplypipe 23 entering the bottom of a wash vessel 24 and pass upward betweenpieces of some porous substance 25, such as coke, which exposes a greatextent of surface, upon which water is sprayed by means of a sprayer 26,so that the sulfurous anhydrid gas coming in contact with the moistsurface forms with the water diluted sulfurous acid, which is collectedat the'bottom inthe same manner as before.

From the top of the wash vessel 24 the' gases pass by a perforated pipe27 into the bottom of a wash vessel 28, which contains a suflicientquantity of water 29 or other suitable liquid which will recoverammonia. I have found that in this process ammonia is formed, which isprobably due to the acid filled with a solution 32 of caustic potash,

which serves to effectually arrestany trace of sulfurous acid orcarbonic acid gas, and forming sulfate of potassium, which is valuablein the arts. From the top of the vessel about half filled with calciumchlorid 34 to take u the moisture. This vessel is used when ry nitrogenis required for use as a preservative, but in other cases, when thenitrogen is not so used, the calcium chlorid may be omitted. From thetop of the latter vessel the gas passes to a suction pump 35, whichcreates the current which draws the air into the furnace and the gasesthrough the series of chambers, and, which likewise, forces the nitrogengas into a suitable receiver 36, from which it may be drawn out asrequired for use.

In order to economize in respect of the chemical reagents in the vessels31, 33, there is provided a bypass pipe 37 having a valve 38, which isopened in commencing the process, and is closed as soon as the gas issufficiently free from oxygen. On the other side of the pump is adischarge p'pe 39 havin a valve 40 therein. A valve 41 is interposedbetween the vessels 24 and 28, and a valve 42 between the suction pumpand the receiver. The valves 38 and 40 are opened and the valves 41 and42 are closed on commencing the process, and the gas emerging throughthe pi e 39 is tested until it is found to be su ciently free fromoxygen, and then said valves are closed and the valves 41, 42, areopened, and the gas is passed into the receiver 36.

It will be understood that in all cases the vessels are composed ofsuitable material, such as earthenware, or, in certain cases, of ironlined with lead, to withstand the action of the acids passingtherethrough. It is also important that said vessels are made perfectlyair-tight. 1

I have found that with the above apparatus nitrogen of great purity canbe obtained from the atmosphere. In practicing the process, it has beenmy custom to reject all nitrogen gas which does not reach a purity of99.6 to 99.8 per cent. Generally speaking,

it is only retained at the latterdegree of purity. By, lacingiron'filings in the re- '31 the gases pass into a vessel 33 which iscentage of oxygen, .2 per cent., is removed,

and the receiver then contains absolutely above process is very muchless than those by processes heretofore attempted commercially, so faras my knowledge extends.

I claim 1. An apparatus for obtainin nitrogen from atmospheric airconsisting of a furnace of considerable area in proportion to its heightto expose a large body of sulfur to oxidation and so concentrated as tocom 1 the whole of the air supplied-to said sul ur to flow into contactwith the sulfur in the furnace, means for supplying sulfur and air atoneend of said furnace, a conduit at the other end ofsaid furnace for theresulting gases, means for removing from said gases the sublimatedsulfur, means for washing from said gases the sulfurous acid, and meansfor confining the residual nitrogen, substantially as described.

2. An apparatus for obtaining nitrogen from atmospheric air comprising afurnace of considerable area in proportion to its height and having atop sloplng downward from the inlet to the outlet of the furnace, meansfor'supplying sulfur and air to the inlet end of said furnace, a conduitat the outlet end of said furnace for the resulting gases, means forremoving from said gases the excess of sulfur and the sulfurous acid, asuction pump at the advance end of the conduit for drawing the air intothe furnace and the gases from said furnace, and means for confining thenitrogen, substantiallyas described.

3. An apparatus for obtaining nitrogen from atmosphericvair comprising afurnace of considerable area in proportion to its height and having atop and bottom both sloping downward from the inlet to the outlet of thefurnace, means for supplying sulfur and air to the inlet end of saidfurnace,

a conduit at the outlet end of said furnace for the resulting gases,means for removing from said gases the excess of sulfur and thesulfurous acid, a suction pump at the advance end of the conduit fordrawing the air into the furnace and the gases from said furnace, andmeans for confining the nitrogen, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

, CHARLES BLAGBURN. Witnesses: FRANCIS M. WRIGHT, D. B. RICHARDS.

